Os tentilhões de Darwin escolhem parceiros para acasalar parecidos com os pais.

Darwin’s finches choose parent lookalikes as mates

A preference for mating with similar individuals can have a key role in speciation. Research on Darwin’s finches suggests that individuals might use the likeness of their parents as a guide for choosing mates. 

Lewis G. Spurgin & Tracey Chapman

New species form when groups of individuals in a population become reproductively isolated and can no longer mate with each other to produce living, healthy offspring. For decades, evolutionary biologists have sought to understand the links between an individual’s choice of mate and reproductive isolation between populations and species¹. Writing in Proceedings of the National Academy of Sciences, Grant and Grant² provide evidence suggesting that two species of Darwin’s finch learn features of their parents early in life and use this knowledge to inform their choice of mate in adulthood, a process known as sexual imprinting. Their study raises fascinating questions about the roles of learning and genetics in mate choice, and how matings between similar individuals (assortative mating) drive the evolution of new species.

Darwin’s finches live in the Galapagos archipelago. They are an iconic group of approximately 15 bird species that have contributed hugely to our understanding of natural selection and speciation^3–5. Previous work has shown that the cultural inheritance of song can promote reproductive isolation between different species of Darwin’s finch⁶. However, it was not known whether sexual imprinting based on morphological features such as body size and beak characteristics could similarly promote reproductive isolation, or play a part in the rare cases of mating between species that produce hybrid individuals. 

If sexual imprinting is key in directing mate choice, then individuals should choose mates that resemble their parents, and also themselves. In addition, if sexual imprinting contributes to matings between species, then the parents of the hybrid individuals that result from such matings should more closely resemble the other species than their own. To test these hypotheses, Grant and Grant analysed 22 years of data on body size, beak size and beak shape in two finch species — Geospiza fortis and Geospiza scandens — living on the same island.

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FREE PDF GRATIS: Nature